{"record":{"id":"7841416ff858677f","repo":"hibernate/hibernate-orm","slug":"couldn-t-load-or-define-class-classname","errorCode":null,"errorMessage":"Couldn't load or define class [{className}]","messagePattern":"Couldn't load or define class \\[(.+?)\\]","errorType":"exception","errorClass":"RuntimeException","httpStatus":null,"severity":"error","filePath":"hibernate-core/src/main/java/org/hibernate/bytecode/internal/bytebuddy/ByteBuddyState.java","lineNumber":200,"sourceCode":"\t\t\tif ( result.getClassLoader() == referenceClass.getClassLoader() ) {\n\t\t\t\treturn result;\n\t\t\t}\n\t\t}\n\t\tcatch (ClassNotFoundException e) {\n\t\t\t// Ignore\n\t\t}\n\t\ttry {\n\t\t\treturn make( makeClassFunction.apply( byteBuddy, new FixedNamingStrategy( className ) ) )\n\t\t\t\t\t.load( referenceClass.getClassLoader(),\n\t\t\t\t\t\t\tresolveClassLoadingStrategy( referenceClass ) )\n\t\t\t\t\t.getLoaded();\n\t\t}\n\t\tcatch (LinkageError e) {\n\t\t\ttry {\n\t\t\t\treturn referenceClass.getClassLoader().loadClass( className );\n\t\t\t}\n\t\t\tcatch (ClassNotFoundException ex) {\n\t\t\t\tthrow new RuntimeException( \"Couldn't load or define class [\" + className + \"]\", e );\n\t\t\t}\n\t\t}\n\t}\n\n\tprivate Class<?> load(Class<?> referenceClass, TypeCache<TypeCache.SimpleKey> cache,\n\t\t\tTypeCache.SimpleKey cacheKey, Function<ByteBuddy, DynamicType.Builder<?>> makeProxyFunction) {\n\t\treturn cache.findOrInsert(\n\t\t\t\treferenceClass.getClassLoader(),\n\t\t\t\tcacheKey,\n\t\t\t\t() -> make( makeProxyFunction.apply( byteBuddy ) )\n\t\t\t\t\t\t.load( referenceClass.getClassLoader(),\n\t\t\t\t\t\t\t\tresolveClassLoadingStrategy( referenceClass ) )\n\t\t\t\t\t\t.getLoaded(),\n\t\t\t\tcache\n\t\t);\n\t}\n\n\tpublic Unloaded<?> make(Function<ByteBuddy, DynamicType.Builder<?>> makeProxyFunction) {","sourceCodeStart":182,"sourceCodeEnd":218,"githubUrl":"https://github.com/hibernate/hibernate-orm/blob/fad1729dce015f908198d57a8d80274a30f905a5/hibernate-core/src/main/java/org/hibernate/bytecode/internal/bytebuddy/ByteBuddyState.java#L182-L218","documentation":"Error \"Couldn't load or define class [{className}]\" thrown in hibernate/hibernate-orm.","triggerScenarios":"Bytecode enhancement, proxy creation, or lazy interception is applied to an incompatible class or configuration.","commonSituations":"Build-time enhancement with module-system restrictions, mismatched Hibernate versions between build and runtime, or hibernate.bytecode.provider=none with a model that needs proxies.","solutions":["Open and export the entity package to Hibernate ORM (module-info: 'opens com.acme.model to org.hibernate.orm.core') or move enhancement to build time."],"exampleFix":"Open and export the entity package to Hibernate ORM (module-info: 'opens com.acme.model to org.hibernate.orm.core') or move enhancement to build time.","handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"fad1729dce015f908198d57a8d80274a30f905a5","analyzedAt":"2026-08-22T04:13:57.527Z","schemaVersion":2},"datasetVersion":"2026-08-22T09:17:25.309Z"}